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[PATCH 08/20] nubus: generate bus error when attempting to access empty
From: |
Mark Cave-Ayland |
Subject: |
[PATCH 08/20] nubus: generate bus error when attempting to access empty slots |
Date: |
Sun, 12 Sep 2021 08:49:02 +0100 |
According to "Designing Cards and Drivers for the Macintosh Family" any attempt
to access an unimplemented address location on Nubus generates a bus error.
MacOS
uses a custom bus error handler to detect empty Nubus slots, and with the
current
implementation assumes that all slots are occupied as the Nubus transactions
never fail.
Switch nubus_slot_ops and nubus_super_slot_ops over to use
{read,write}_with_attrs
and hard-code them to return MEMTX_DECODE_ERROR so that unoccupied Nubus slots
will generate the expected bus error.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
hw/nubus/nubus-bus.c | 34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)
diff --git a/hw/nubus/nubus-bus.c b/hw/nubus/nubus-bus.c
index e250abfda0..8a3731cab6 100644
--- a/hw/nubus/nubus-bus.c
+++ b/hw/nubus/nubus-bus.c
@@ -20,23 +20,23 @@ static NubusBus *nubus_find(void)
return NUBUS_BUS(object_resolve_path_type("", TYPE_NUBUS_BUS, NULL));
}
-static void nubus_slot_write(void *opaque, hwaddr addr, uint64_t val,
- unsigned int size)
+static MemTxResult nubus_slot_write(void *opaque, hwaddr addr, uint64_t val,
+ unsigned size, MemTxAttrs attrs)
{
- /* read only */
trace_nubus_slot_write(addr, val, size);
+ return MEMTX_DECODE_ERROR;
}
-static uint64_t nubus_slot_read(void *opaque, hwaddr addr,
- unsigned int size)
+static MemTxResult nubus_slot_read(void *opaque, hwaddr addr, uint64_t *data,
+ unsigned size, MemTxAttrs attrs)
{
trace_nubus_slot_read(addr, size);
- return 0;
+ return MEMTX_DECODE_ERROR;
}
static const MemoryRegionOps nubus_slot_ops = {
- .read = nubus_slot_read,
- .write = nubus_slot_write,
+ .read_with_attrs = nubus_slot_read,
+ .write_with_attrs = nubus_slot_write,
.endianness = DEVICE_BIG_ENDIAN,
.valid = {
.min_access_size = 1,
@@ -44,23 +44,25 @@ static const MemoryRegionOps nubus_slot_ops = {
},
};
-static void nubus_super_slot_write(void *opaque, hwaddr addr, uint64_t val,
- unsigned int size)
+static MemTxResult nubus_super_slot_write(void *opaque, hwaddr addr,
+ uint64_t val, unsigned size,
+ MemTxAttrs attrs)
{
- /* read only */
trace_nubus_super_slot_write(addr, val, size);
+ return MEMTX_DECODE_ERROR;
}
-static uint64_t nubus_super_slot_read(void *opaque, hwaddr addr,
- unsigned int size)
+static MemTxResult nubus_super_slot_read(void *opaque, hwaddr addr,
+ uint64_t *data, unsigned size,
+ MemTxAttrs attrs)
{
trace_nubus_super_slot_read(addr, size);
- return 0;
+ return MEMTX_DECODE_ERROR;
}
static const MemoryRegionOps nubus_super_slot_ops = {
- .read = nubus_super_slot_read,
- .write = nubus_super_slot_write,
+ .read_with_attrs = nubus_super_slot_read,
+ .write_with_attrs = nubus_super_slot_write,
.endianness = DEVICE_BIG_ENDIAN,
.valid = {
.min_access_size = 1,
--
2.20.1
- [PATCH 04/20] nubus: use bitmap to manage available slots, (continued)
- [PATCH 04/20] nubus: use bitmap to manage available slots, Mark Cave-Ayland, 2021/09/12
- [PATCH 05/20] nubus: move slot bitmap checks from NubusDevice realize() to BusClass check_address(), Mark Cave-Ayland, 2021/09/12
- [PATCH 03/20] nubus-device: add device slot parameter, Mark Cave-Ayland, 2021/09/12
- [PATCH 07/20] nubus: add trace-events for unassigned slot accesses, Mark Cave-Ayland, 2021/09/12
- [PATCH 08/20] nubus: generate bus error when attempting to access empty slots,
Mark Cave-Ayland <=
- [PATCH 09/20] macfb: don't register declaration ROM, Mark Cave-Ayland, 2021/09/12
- [PATCH 10/20] nubus-device: remove nubus_register_rom() and nubus_register_format_block(), Mark Cave-Ayland, 2021/09/12
- [PATCH 11/20] nubus-device: add romfile property for loading declaration ROMs, Mark Cave-Ayland, 2021/09/12
- [PATCH 13/20] nubus-bridge: introduce separate NubusBridge structure, Mark Cave-Ayland, 2021/09/12
- [PATCH 12/20] nubus: move nubus to its own 32-bit address space, Mark Cave-Ayland, 2021/09/12